This invention relates to a grommet for passing and holding a member, such as a wire harness, relative to a through hole in a mounting plate of an vehicle or the like.
Many wire harnesses are installed, for example, on a vehicle body of an automobile, and among these wire harnesses, there are some each passed through a through hole in a vehicle body panel. When the wire harness is passed through the through hole, the wire harness contacts a peripheral edge of the through hole during the running of the automobile, so that a sheath (insulating material) of the wire harness may be damaged, and besides rain water, dust and others may intrude into a car room through a gap between the wire harness and the peripheral edge of the through hole. Therefore, a grommet, made of an elastic material such as rubber, is mounted in the through hole so that the wire harness will not contact the peripheral edge of the through hole, and the grommet closes the gap between the wire harness and the peripheral edge of the through hole. There are known grommets of various shapes, and one example is disclosed in JP-A-8-140246.
As shown in FIG. 4, this grommet includes a cylindrical mounting portion 22, having an engagement groove 21 which is formed in an outer peripheral face thereof, and can be fitted in an inner peripheral edge portion of a through hole 20, a cylindrical wire harness-fixing portion 24, which can be fitted on and fixed to a wire harness 23, and a closure portion 25 closing a space between the mounting portion 22 and the wire harness-fixing portion 24, these portions 22, 24 and 25 being formed or molded integrally with one another. The closure portion 25 has a cylindrical shape gradually decreasing in diameter, and is disposed within the mounting portion 22. Namely, a larger-diameter portion (one end portion) of the closure portion 25 is connected to the mounting portion 22 while a smaller-diameter portion (the other end portion) thereof is connected to one end of the wire harness-fixing portion 24, and the mounting portion 22, the closure portion 25 and the wire harness-fixing portion 24 are interconnected to assume a generally Z-shaped cross-section, so that the wire harness 23, even when fixed to the grommet 26 (that is, to the wire harness-fixing portion 24), can be bent and moved.
When mounting operation of this grommet 26 in the through hole 20 is performed, the wire harness 23 is fixed to the wire harness-fixing portion 24, and in this condition the wire harness 23, passing through the through hole 20, or the wire harness-fixing portion 24 is pulled in its longitudinal direction, that is, in a direction from the other end of the closure portion 25 to the one end thereof. As a result, the wire harness-fixing portion 24 is moved along the length of the wire harness 23. At this time, the smaller-diameter portion of the closure portion 25 is moved along the length of the wire harness 23, and this smaller-diameter portion of the closure portion 25 is moved forwardly beyond the position, at which the larger-diameter portion thereof is connected to the mounting portion 22, in the direction of pulling of the wire harness 23, and the grommet 26 is first formed, for example, into a funnel-like shape as shown in FIG. 5, and then the mounting portion 22 is pulled toward the through hole. Then, that side of an outer peripheral portion of the mounting portion 22, held in contact with the peripheral edge portion of the through hole 20, is pressed and deformed to be forced into the through hole 20, so that the peripheral edge portion of the through hole 20 is engaged in the engagement groove 21, thus effecting the mounting of the grommet 26 in the through hole 20.
When mounting operation of the above grommet in a through hole 20 in a vehicle body panel is performed, the wire harness-fixing portion 24 or the wire harness 23 is pulled, thereby forcing the one side of the mounting portion 22 into the through hole through the closure portion 25. When the mounting portion 22 is pulled, the grommet is formed into the funnel-like shape as shown in FIG. 5. Namely, before this pulling operation, the other end portion of the closure portion 25 is disposed rearwardly of the one end portion thereof in the pulling direction, and when the pulling operation is effected, the other end portion is moved into the position disposed forwardly of the one end portion in the pulling direction, so that the closure portion is held in its extended condition. Therefore, after mounting the grommet 26 in the through hole 20, the closure portion 25 of the grommet 26, in some cases, remains in the extended condition. In this case, for restoring the closure portion 25 (that is; the grommet 26) into its original shape, the wire harness-fixing portion 24 and the wire harness 23 must be moved in a direction opposite to the above moving direction by man power, and therefore the efficiency of the operation is low.
It is therefore an object of the present invention to provide a grommet which can be mounted efficiently.
In order to achieve the above object, according to the present invention, there is provided a grommet comprising:
a first cylindrical portion for passing a member threthrough;
a second cylindrical portion, connected to the first cylindrical portion through an annular connection portion formed at an outer peripheral face of the first cylindrical portion, the second cylindrical portion having a fitting groove which formed in an outer peripheral face thereof for fitting on an inner peripheral edge of a through hole in a mounting plate;
a first junction portion, formed between the annular connection portion and the first cylindrical portion; and
a second junction portion, formed between the annular connection portion and the second cylindrical portion;
wherein a form of the grommet changes between a first state in which an angle formed the annular connection portion with the first cylindrical portion in cross section is an acute angle and a second state in which an angle formed the annular connection portion with the first cylindrical portion in cross section is obtuse angle; and
wherein at least one of the first cylindrical portion and the second cylindrical portion are formed so that the grommet autonomously restores in the first state.
Preferably, the first junction portion is positioned at inside of the second cylindrical portion in the first state. The first junction portion is positioned at outside of the second cylindrical portion in the second state.
Preferably, the first junction portion has a thickness in an axial direction of the first cylindrical portion larger than a thickness of the annular connection portion.
Preferably, the first junction portion has a thickness in an axial direction of the first cylindrical portion larger than a thickness of the first cylindrical portion.
Preferably, the second junction portion has a thickness in an axial direction of the first cylindrical portion larger than a thickness of the annular connection portion.
In this construction, the first and second junction portion have the increased stiffness, and have an increased force acting to or tending to restore itself into the first shape. Therefore, even when the grommet is extended, it is restored into the first shape either by itself or merely by applying a small force thereto, and therefore the efficiency of the operation is enhanced.
Preferably, a thickness portion is formed over a periphery of at least one of the first junction portion and the second junction portion.
In this configuration, at least one of the first junction portion and the second junction portion are increased in thickness of the entire periphery thereof, the stiffness of at least one of the first junction portion and the second junction portion is surely increased, and therefore mounting operation of the grommet can be effected efficiently.